Light-emitting devices may include a wavelength-converting region (e.g., phosphor region) which can absorb light from a light-generating region (e.g., semiconductor region within an LED) and emit light having a different wavelength. As a result, a light-emitting device incorporating a wavelength-converting region can emit light having wavelength(s) that may not be possible using an LED without such regions.
For example, a GaN-based LED may emit blue light which can be converted to yellow light by a (Y,Gd)(Al,Ga)G:Ce3+ or “YAG” (yttrium, aluminum, garnet) phosphor. Any unconverted blue light can be filtered so that the light-emitting device can emit only yellow light. In another example, the combined emission from a GaN-based LED and a YAG phosphor may generate white light as a result of combining blue light emitted from the LED and yellow light generated by the phosphor due to the conversion of some of the blue light.